1. Field Of Invention
The present invention is directed to an improved tampon applicator. More particularly, the present invention is directed to a tampon applicator having a plastic-type body or coating that has been treated. Even more particularly, the tampon applicator is either molded of a polymer resin, or coated with a polymer resin, with the outside surface of the applicator then treated with infrared radiation.
Consumers desire tampon applicators that make pledget insertion easier, more convenient and less messy. In particular, for environmental reasons as well as for convenience of disposal, consumers desire applicators, especially tampon applicators, that are both biodegradable and water-soluble. An example of a water-soluble polymer used for making flushable applicators is polyvinyl alcohol (also referred to herein as "PVOH").
However, PVOH, in particular, is known to become sticky on contact with moist surfaces or under humid conditions. Heat treatment of the PVOH applicator provides crystallization that increases water resistance, but too much heat makes PVOH unacceptably stiff and brittle.
The present invention overcomes the disadvantages described above associated with tampon applicators made from water-soluble polymers in an efficient manner, and provides tampon applicators either made from, or coated with, water-soluble polymers that are able to withstand exposure to moisture, but are not unacceptably stiff. The present invention accomplishes the foregoing by heating only the outside of the applicator with infrared radiation.
U.S. Pat. No. 5,782,794, the grandparent of the present application, discloses a novel set of plasticizers suitable for use with PVOH that, in conjunction, produce a molded product having improved stability, ease of molding, and utility for tampon applicators. The disclosure of U.S. Pat. No. 5,782,794 in its entirety is incorporated herein by reference.
2. Description of the Prior Art
Tampon applicators typically are constructed from two telescoping tubes. One tube, a barrel, encloses the pledget, and the other tube, a plunger, is used to eject the pledget out of the barrel during insertion. Thus, it is essential that the tubes telescope smoothly to facilitate ejection. Any stickiness or other adhesions between the two tubes can result in poor ejection of the pledget, which in turn can make insertion of the pledget difficult, painful, or impossible. One solution to the foregoing problem is to make the diameter of the plunger less than the diameter of the barrel. However, if the plunger is much less in diameter than the barrel to prevent sticking together, the plunger will most likely disassemble from the barrel.
Furthermore, the ability of the barrel to be inserted smoothly, without dragging on the delicate vaginal tissue, is very important not only for users comfort but also for proper insertion of the pledget. Once again, any stickiness or adhesion sites on the outer surface of the barrel will impede proper insertion.
Tampon applicators formed from certain polymer resins, when dry, have glide characteristics similar to traditional plastic tampon applicators. Thus, such polymer resin tampon applicators would be expected to have optimal qualities for insertion, minimal drag on insertion and smooth telescoping of the barrel and plunger. In addition, these polymer resin tampon applicators remain dispersible and biodegradable on disposal in water.
However, the very ability of the polymer resin tampon applicators to disperse in water also creates certain drawbacks. Water-soluble polymer resins, can become sticky on contact with moist surfaces, bodily fluids or under humid conditions. Thus, tampon applicators formed from polymer resins tend to become tacky in the very environment for which it is designed. This in turn makes insertion more difficult, since the outer tube can become gummy or tacky upon insertion. Another potential problem should such a polymer resin applicator be exposed to moisture, is that the barrel and plunger may not telescope properly. The barrel and plunger may even become glued together, requiring a much greater force to eject the tampon pledget from the applicator. Additionally, humidity from the environment can permeate the packaging used to store the polymer resin tampon applicator and, thus, cause the same problems. Humidity may even cause the applicator to stick to the wrapper.